Relationship between locomotive syndrome and sarcopenia in patients with cancer: a prospective cohort study

Abstract Background Locomotive syndrome (LS) and sarcopenia are both associated with impaired mobility; however, their relationship in patients with cancer remains unclear. This study aimed to clarify the relationship between severe LS and sarcopenia and its individual components in patients with cancer. Methods This prospective cohort study included patients hospitalized for cancer treatment who were prescribed rehabilitation at two university hospitals. LS and sarcopenia were assessed at baseline and at the six-month follow-up. LS stage 3 was defined as severe LS. Sarcopenia was diagnosed according to the Asian Working Group for Sarcopenia criteria based on gait speed, grip strength, and skeletal muscle mass index. The association between severe LS and sarcopenia was analyzed using Fisher's exact test. Gait speed, grip strength, and skeletal muscle mass index were compared between patients with and without severe LS using Welch's t-test. Results A total of 114 patients were included in the analysis (mean age, 68.1 ± 12.6 years; 64 men and 50 women). At baseline, 26 patients had severe LS and 11 had sarcopenia. Severe LS was not significantly associated with sarcopenia (4/26 [15.4%] vs. 7/88 [8.0%], p = 0.27). Patients with severe LS had lower gait speed (80.5 ± 20.1 vs. 103.8 ± 18.8 cm/s, p < 0.01) and grip strength (22.7 ± 8.4 vs. 26.8 ± 7.4 kg, p = 0.03), whereas skeletal muscle mass index did not differ significantly between the groups (7.6 ± 1.5 vs. 7.4 ± 1.3 kg/m², p = 0.60). At six months, 31 patients had severe LS and 11 had sarcopenia. The association between severe LS and sarcopenia remained non-significant (6/31 [19.4%] vs. 5/83 [6.0%], p = 0.07). Patients with severe LS continued to have lower gait speed (77.5 ± 21.6 vs. 105.4 ± 20.0 cm/s, p < 0.01) and grip strength (21.7 ± 7.3 vs. 27.9 ± 6.8 kg, p < 0.01), while skeletal muscle mass index remained comparable between the groups (7.0 ± 1.4 vs. 7.5 ± 1.2 kg/m², p = 0.08). Conclusions Severe LS was not significantly associated with sarcopenia at baseline or at the six-month follow-up in patients with cancer. However, patients with severe LS consistently exhibited lower gait speed and grip strength without a significant difference in skeletal muscle mass index. These findings suggest that severe LS and sarcopenia represent related but distinct aspects of physical impairment in patients with cancer, and that functional impairment associated with severe LS may occur without a concomitant reduction in skeletal muscle mass.